中文：

市盈率是指上市公司股票的每股盈利与每股市价的比值。市盈率反映了投资者对上市公司未来业绩的预期，是衡量股票投资价值的重要指标之一。

市盈率的计算公式为：市盈率 = 每股盈利 / 每股市价。其中，每股盈利是指上市公司在一定会计期间内每股股票的净利润，而每股市价则是指股票在市场上的交易价格。

市盈率可以分为静态市盈率和动态市盈率。静态市盈率是指以上一年度的每股盈利为标准计算的市盈率，而动态市盈率则是指以未来预期的每股盈利为标准计算的市盈率。

一般来说，市盈率越低，说明股票的投资价值越大。但投资者需要注意的是，市盈率并不能完全反映股票的投资价值，还需要结合其他财务指标和非财务指标进行综合分析。

英文：

The P/E ratio, or price-earnings ratio, is the ratio of the price of a stock to its earnings per share. It is a measure of the price investors are willing to pay for each unit of the company's earnings, and it provides an indicator of the stock's value.

The P/E ratio is calculated by dividing the price of a stock by its earnings per share. The earnings per share represent the net profit earned by each share of the company's stock during a given period of time, while the stock price is the market value of a single share of the stock.

There are two types of P/E ratios: trailing P/E and forward P/E. The trailing P/E is based on the past year's earnings, while the forward P/E is based on the expected earnings for the next year.

Generally speaking, a lower P/E ratio indicates a higher value for the stock. However, investors should note that the P/E ratio alone cannot fully reflect the investment value of a stock. It needs to be analyzed in combination with other financial and non-financial indicators.